Speckle Noise Reduction using Local Binary Pattern

AbstractA novel local binary pattern (LBP) based adaptive diffusion for speckle noise reduction is presented. The LBP operator unifies traditionally divergent statistical and structural models of region analysis. We use LBP textons to classify an image around a pixel into noisy, homogenous, corner and edge regions. According to different types of regions, a variable weight is assigned in to the diffusion equation, so that our algorithm can adaptively encourage strong diffusion in homogenous/noisy regions and less on the edge/corner regions. The diffusion preserves edges, local details while diffusing more on homogenous region. The experiments results are evaluated both in terms of objective metric and the visual quality

Real-time On-board Object Tracking for Cooperative Flight Control

One of possible cooperative Situations for flights could be a scenario when the decision on a new path is taken by A Certain fleet member, who is called the leader. The update on the new path is Transmitted to the fleet members via communication That can be noisy. An optical sensor can be used as a back-up for re-estimating the path parameters based on visual information. For A Certain topology, the issue can be solved by continuous tracking of the leader of the fleet in the video sequence and re-adjusting parameters of the flight, accordingly. To solve such a problem of a real time system has been developed for Recognizing and tracking 3D objects. Any change in the 3D position of the leading object is Determined by the on-board system and adjustments of the speed, pitch, yaw and roll angles are made to sustain the topology. Given a 2D image acquired by an on-board camera, the system has to perform the background subtraction, recognize the object, track it and evaluate the relative rotation, scale and translation of the object. In this paper, a comparative study of different algorithms is Carried out based on time and accuracy constraints. The solution for 3D pose estimation is provided based on the system of invariant Zernike moments. The candidate techniques solving the complete set of procedures have been Implemented on Texas Instruments TMS320DM642 EVM board. It is shown That 14 frames per second can be processed; That supports the real time Implementation of the tracking system with the reasonable accuracy

Sparse-View CT Reconstruction Based on Nonconvex L1 − L2 Regularizations

The reconstruction from sparse-view projections is one of important problems in computed tomography (CT) limited by the availability or feasibility of obtaining of a large number of projections. Traditionally, convex regularizers have been exploited to improve the reconstruction quality in sparse-view CT, and the convex constraint in those problems leads to an easy optimization process. However, convex regularizers often result in a biased approximation and inaccurate reconstruction in CT problems. Here, we present a nonconvex, Lipschitz continuous and non-smooth regularization model. The CT reconstruction is formulated as a nonconvex constrained L1 − L2 minimization problem and solved through a difference of convex algorithm and alternating direction of multiplier method which generates a better result than L0 or L1 regularizers in the CT reconstruction. We compare our method with previously reported high performance methods which use convex regularizers such as TV, wavelet, curvelet, and curvelet+TV (CTV) on the test phantom images. The results show that there are benefits in using the nonconvex regularizer in the sparse-view CT reconstruction

Final Report, Next-Generation Mega-Voltage Cargo-Imaging System for Cargo Conainer Inspection, March 2007

The UNLV Research Foundation, as the primary award recipient, teamed with Varian Medical Systems-Security & Inspection Products and the University of Nevada Las Vegas (UNLV) for the purpose of conducting research and engineering related to a "next-generation" mega-voltage imaging (MVCI) system for inspection of cargo in large containers. The procurement and build-out of hardware for the MVCI project has been completed. The K-9 linear accelerator and an optimized X-ray detection system capable of efficiently detecting X-rays emitted from the accelerator after they have passed through the device is under test. The Office of Science financial assistance award has made possible the development of a system utilizing a technology which will have a profound positive impact on the security of U.S. seaports. The proposed project will ultimately result in critical research and development advances for the "next-generation" Linatron X-ray accelerator technology, thereby providing a safe, reliable and efficient fixed and mobile cargo inspection system, which will very significantly increase the fraction of cargo containers undergoing reliable inspection as the enter U.S. ports. Both NNSA/NA-22 and the Department of Homeland Security's Domestic Nuclear Detection Office are collaborating with UNLV and its team to make this technology available as soon as possible

An Improved Polling Scheme for Voice Support in IEEE 802.11 Wireless network

In this paper, we present a polling scheme, which allows for augmenting the support of voice communications in point co-ordination function (PCF) of IEEE 802.11 wireless networks. In this scheme, the access point (AP) of the basic service set (BSS) maintains two polling lists, i.e. the talking list and the silence list. Based on the talking status of the stations identified via silence detection, the two lists are dynamically adjusted by the AP. Temporary removal is applied to the stations in the silence list to further upgrade the performance. The conducted study based on simulation has shown that the proposed scheme is able to support more voice stations and has a lower packet loss rate compared to that obtained by four reference polling algorithms

An Enhanced Direction-based Location Update Scheme for PCS networks

Future personal communication service (PCS) networks consider smaller cells to accommodate continuously growing population of subscribers. Frequently performed location updates caused by such an infrastructure incur extensive signaling and consequently higher cost. Thus, new strategies are demanded to locate mobile users more efficiently. Among several proposals, the direction-based location update (DBLU) scheme uses a dynamic strategy such that the mobile users update their locations only when a change of direction occurs. To locate users, the system pages cells along the direction of initial move. The scheme works well when the change of direction is infrequent and the ratio of location update cost to paging cost is low. Otherwise, the location update, and consequently the overall cost increase significantly. To attack this problem, we propose an enhanced direction-based location update (EDBLU) scheme, which takes into account both the moving distance and the moving direction. We analyze the performance of the EDBLU under different mobility patterns and call-to-mobility ratios based on a 2D Markov walk model. The numerical results demonstrate that the proposed scheme augments the performance reported by the distance-based and the direction-based methods

Hybrid Location Update Scheme for Future PCS networks

Future personal communication service (PCS) networks consider smaller cells to accommodate continuously growing population of subscribers. That results in frequent location update and consequently higher signaling cost. Among various schemes proposed for improving the efficiency of location management, the distance-based and the direction-based location update methods work well for just certain mobility patterns. In this paper, we propose a hybrid location update (HLU) scheme, which takes into account both the moving distance and the moving direction when deciding on updating the location. We analyze the performance of the HLU under different mobility patterns and call-to-mobility ratios based on a 2D Markov walk model. The numerical results demonstrate that the HLU scheme can achieve better performance than the distance-based or the direction-based methods applied individually

Intra-domain Mobility Management for a Tree-type network Topology

A mechanism is devised for performing handoff in mobile networks. It is based on the micro-mobility concept and packet forwarding strategy. With a comparably small signaling overhead, the mechanism provides the smooth handoff when mobile nodes change the points of their attachment. The routing is based on a flat routing table look-up with caching the binding information on current location of mobile nodes. The simulation results show a lower rate of packet losses and high throughput than that encountered for Mobile IP and Cellular IP

Performance Analysis of Channel DE-allocation Schemes for Dynamic Resource Allocation in GSM/GPRS networks

Channel de-allocation for GSM voice call (DASV) has been considered for dynamic resource allocation in GSM/GPRS networks. Two new de-allocation schemes are proposed: de-allocation for GPRS packet (DASP) and de-allocation for both GSM voice call and GPRS packet (DASVP). An analytic model with general GPRS data channel requirement is derived to evaluate the performance of the schemes in terms of GSM voice call incompletion probability, GPRS packet dropping probability, average GPRS packet transmission time and channel utilisation